Human Factors in Design & Digital Systems

We apply human factors expertise to control room design, alarm management, HMI and digital interface development, and human-system integration projects in high-hazard and safety-critical industries.

Every engagement is led by Dr. Chizaram Dagogo-Nwankwo, Chartered Ergonomist (C.ErgHF, CIEHF), with published peer-reviewed research in human factors and process safety and direct experience across oil and gas, energy, chemical, and healthcare systems.

Why human factors in design matters

The accidents most commonly attributed to operator error in high-hazard industries share a pattern. The operators had the information they needed. The interface did not give it to them in a form they could use quickly and correctly under the conditions that existed at the time.

Control rooms where alarms fire faster than operators can acknowledge them. HMI displays that require three screen transitions to access the data needed for an abnormal condition response. Alarm floods that produce hundreds of alerts in the first minutes of a plant upset, guaranteeing that the most important ones are missed. Digital systems designed by software engineers for ease of coding rather than for the cognitive demands of the people operating them.

These are design failures. The operator is the last layer of defence between the failure and the consequence. When the design makes reliable human performance improbable, attributing the outcome to human error is not an explanation. It is a conclusion that prevents the right question from being asked.

Human factors in design addresses those questions before the system is built or before an upgrade goes live, not after an incident has answered them.

Who needs this service

1. Control room modernisation and DCS upgrade projects
   Process industry operators upgrading distributed control systems, replacing legacy HMI, or building new control rooms need human factors input at the design stage. ISO 11064 (ergonomics of control centres) and EEMUA 191 (alarm systems guidance) set the standards against which regulators and insurers assess control room design. Projects that address human factors only during commissioning carry the cost of retrofitting what could have been designed correctly.
2. Alarm management projects
   UK high-hazard operators managing alarm rationalisation programmes, EEMUA 191 compliance assessments, or alarm system redesign as part of a DCS replacement. Alarm management is one of the most documented contributors to major accident events in process industries. Poorly designed alarm systems were cited in the Milford Haven explosion in 1994 and in the Texas City incident in 2005.
3. New facility design (FEED and detailed design)
   Project teams developing new plant, offshore platforms, or production facilities where control room layout, operator console design, and HMI architecture need to be established during FEED. Human factors requirements defined at this stage are incorporated at no additional cost. The same requirements identified at commissioning become change requests.
4. Digital health and clinical systems
   Healthcare organisations implementing electronic patient record systems, clinical decision support tools, or medical device interfaces where poor usability leads to clinical error. The NHS Digital Technology Assessment Criteria (DTAC) and MHRA guidance on medical device software both carry human factors expectations that are often underweighted in procurement and development.
5. Safety-critical software and SCADA systems
   Industrial automation, SCADA, and supervisory control systems in water utilities, energy, and defence where the interface between the operator and the controlled process carries safety implications. IEC 62682 (alarm management for process industries) and ISA-101 (process industry HMI) apply in these environments.
6. Defence and aerospace systems
   Platform human-machine interfaces, mission systems, and ground station design where DEF STAN 00-251 human factors requirements apply. Usability testing and human factors evaluation are specified activities under the standard.

What our service includes

1. Human factors requirements specification
   Before any design work begins, we establish the human performance requirements the system must meet: the tasks the interface needs to support, the conditions under which those tasks will be performed, the response times required, the error-recovery paths that must be available, and the operator populations who will use the system. Requirements specified at this stage drive design decisions rather than react to them.
2. Control room design review (ISO 11064)
   Assessment of control room layout, console configuration, display positioning, lighting, noise, and environmental conditions against ISO 11064. Applied at concept design to shape the specification, at detailed design to verify the layout against the standard, and post-construction to confirm the built environment meets the design intent.
3. Alarm management assessment (EEMUA 191 / IEC 62682)
   Review of the alarm system against EEMUA 191 and IEC 62682 guidance. Covers alarm philosophy, alarm rationalisation status, nuisance alarm identification, alarm flood analysis, and critical alarm identification. For projects replacing alarm systems as part of DCS upgrades, we support the specification of the new alarm philosophy before implementation begins.
4. HMI and interface design review (ISA-101)
   Review of process HMI displays against ISA-101 and human factors design principles. Assesses display hierarchy, navigation structure, process graphic design (colour use, symbol conventions, dynamic elements), and the consistency of the display suite across operating modes. Identifies displays that fail to support reliable situation awareness under abnormal conditions.
5. Usability testing and evaluation
   Structured testing of interfaces with representative users under conditions that approximate real operational demands. Usability testing identifies interaction failures that design review misses because paper-based review cannot replicate the cognitive load of operating a process under time pressure. Applied at prototype stage for new systems and at the acceptance testing stage for procured systems.
6. Human-system integration (HSI) support
   For complex projects where control system, procedures, training, and staffing need to be considered together, we provide HSI support that coordinates the human factors inputs across workstreams rather than treating interface design as an isolated activity. Aligned with the HSI requirements in IOGP 454 and DEF STAN 00-251.
7. Digital UI/UX for safety-critical applications
   Human factors review and design support for clinical systems, industrial apps, and safety-critical mobile and web applications. Distinct from commercial UX design in that the consequences of interaction failure are not measured in abandoned shopping carts. Applied standards include IEC 62366 (usability of medical devices) for healthcare applications and NUREG-0700 for nuclear applications.

What the standards require

The standards governing human factors in control room and interface design are specific and, in regulated sectors, legally material.

• ISO 11064 covers the ergonomics of control centres across seven parts: principles for the design of control centres, principles for the arrangement of control suites, control room layout, workstation layout, displays, controls, and the overall design process. Compliance with ISO 11064 is referenced in HSE guidance and is expected in COMAH safety cases for facilities with control rooms.
• EEMUA 191 (Alarm Systems: A Guide to Design, Management and Procurement) is the UK industry standard for alarm management in process industries. First published in 1999 and updated in 2013, it establishes quantitative performance targets for alarm systems, including the acceptable rate of alarm activations per operator per hour during normal and abnormal operations. Control rooms that routinely exceed these rates carry documented safety risk.
• ISA-101 (Human Machine Interfaces for Process Automation Systems) provides guidance on HMI design philosophy, display hierarchy, and the specific design of process graphics. It complements EEMUA 191 by addressing the display of process information rather than the management of alarms specifically.
• IEC 62682 (Management of Alarms for the Process Industries) is the international standard that aligns with and extends EEMUA 191 for international applications.

Understanding which standards apply to a specific project, and how they interact, is part of the scoping conversation.

Frequently asked questions

Is human factors in control room design a regulatory requirement?
ISO 11064 is referenced in HSE guidance as the applicable standard for control room ergonomics in process industries. For COMAH-regulated facilities, the HSE competent authority inspects control rooms and alarm management systems as part of COMAH inspections. Meeting the standard is not strictly mandatory by name in the COMAH Regulations, but failure to meet it in a facility where a control room operator's performance is a credited safety barrier is likely to draw regulatory scrutiny. For nuclear sites, the ONR's SAPs include specific expectations around control room design. For defence programmes, DEF STAN 00-251 mandates human factors activities including interface evaluation.

When should human factors be applied to a control room design project?
As early in the design process as possible. Human factors requirements should be included in the control room design specification before the layout is fixed, before the DCS supplier is selected, and before display configurations are agreed. Changes made after the DCS is programmed and the control room is built are expensive and often incomplete. The earlier the input, the lower the cost of acting on it.

What is the difference between human factors and UX design?
UX design, as practised in commercial software development, focuses on usability, user satisfaction, and conversion. Human factors in safety-critical systems focuses on human performance and error reduction where the consequences of interaction failure include injury, death, environmental damage, or major asset loss. The methods overlap (both use user research, task analysis, and usability testing) but the standards, the depth of analysis, and the consequences of getting it wrong are different.

Can you carry out a human factors review of an existing control room?
Yes. A review of an existing control room against ISO 11064 and EEMUA 191 provides a gap analysis between current state and the applicable standards. This is used to prioritise improvement work, support a business case for control room modernisation, and provide documented evidence of human factors consideration for regulatory purposes.

Do you work with software development teams on digital system design?
Yes. We work alongside software development teams during the design and testing phases of digital systems in high-hazard and clinical environments. This includes contributing human factors requirements to the design specification, reviewing interface designs against applicable standards at prototype stage, and conducting usability testing at acceptance stage. The earlier we are involved in the development cycle, the less rework the project requires.

Discuss a project

Human factors in design and digital systems engagements are scoped individually based on the system type, the design stage, and the applicable regulatory framework. Contact us with a brief description of the project and we will come back within two working days with a proposed approach.